This invention relates to an improved non-pneumatic tire that can be used primarily as a temporary spare tire. The improved tire is designed to replace the conventional pneumatic spare tire.
Non-pneumatic tires are old in the art. Non-pneumatic solid rubber tires were in use prior to pneumatic tires. As vehicle speeds increased and ride characteristics became more important the need for a better tire structure emerged. The invention of the pneumatic tire provided a solution to the problems and limitations of solid tires.
The pneumatic tire is an efficient structure that has endured as a solution to conventional vehicle requirements. A pneumatic tire is a xe2x80x9ctensile structurexe2x80x9d. Tensile structures always contain a compression member for providing a tensile preload in the tensile member. The tensile member can usually accept no compression and the compression member no tension. In pneumatic tires the cords are the tensile members and the compressed air is the compression member.
The primary drawback of a pneumatic tire is that it is pneumatic. Air contained under pressure can and usually does escape at the most inopportune times at least from the driver""s viewpoint. It is aggravating to find that the spare tire that has been stored in the trunk for years is also flat.
The present invention has no air under pressure. It is a tire structure that performs similarly to a pneumatic tire without requiring pressurized air.
The present invention is a non-pneumatic tire comprising a rim and one or more elastomeric materials bonded to the rim or to one another. The tire has an equatorial plane, an annular tread, and an annular elastomeric body having first and second spaced lateral sides equidistant from the equatorial plane and extending between the tread and the rim. The tire body has a plurality of equally spaced arches forming at least a first series of openings extending from the first side to the second side. The first openings having a height at least one-half the height of the tire side.
In one aspect of the invention, each arch of the non-pneumatic tire has a constant radius of curvature.
In another aspect of the invention, the arches form a second series of openings circumferential and radially offset from the first openings. The second openings preferably have a triangular shape due to the arch configuration.
In another aspect of the invention, the first openings have a height of one-half to three-quarters of the tire side.
In another aspect of the invention, the openings in the non-pneumatic tire extend the fill width of the body. The openings may also vary in size across the width of the body.
Definitions
The invention also may be better understood in the context of the following definitions, which are applicable to both the specification and the appended claims:
xe2x80x9cAxialxe2x80x9d and xe2x80x9caxiallyxe2x80x9d are used herein to refer to lines or directions that are parallel to the axis of rotation of the tire;
xe2x80x9cElastomerxe2x80x9d means a resilient material capable of recovering size and shape after deformation;
xe2x80x9cEquatorial plane (EP)xe2x80x9d means the plane perpendicular to the tire""s axis of rotation and passing through the center of its tread;
xe2x80x9cFootprintxe2x80x9d means the contact patch or area of contact of the tire tread with a flat surface at zero speed and under normal load;
xe2x80x9cNormal loadxe2x80x9d refers to the specific design load for the service condition for a tire;
xe2x80x9cPneumatic tirexe2x80x9d means a laminated mechanical device of generally toroidal shape (usually an open-torus) having beads and a tread and made of rubber, chemicals, fabric, and steel or other materials;
xe2x80x9cRadialxe2x80x9d and xe2x80x9cradiallyxe2x80x9d are used to mean directions radially toward or away from the axis of rotation of the tire;
xe2x80x9cRimxe2x80x9d means a support for a tire or a tire and tube assembly upon which the tire is secured; and
xe2x80x9cTreadxe2x80x9d means a molded rubber component which, when bonded to a tire body, includes that portion of the tire that comes into contact with the road when the tire is under normal load.